Oxoanions are a class of oxygen-bearing anionic molecules that can be formed during industrial processes. Typical oxoanions encountered during commercial processing operations include borate, carbonate, phosphate, sulfate, chromate, and arsenate. These oxoanions can be formed when a substance containing the non-oxygen element of the oxoanion is exposed to oxygen, water, and/or bacteria. For example, during excavation of earthen material, such as mining and milling operations, minerals in rocks can be exposed to oxidizing conditions forming oxoanions in water seepages or process waste streams.
Because of the adverse health and environmental effects associated with many oxoanions, governmental regulatory agencies often limit the level at which certain oxoanions can be discharged with waste water into the environment. As a result, process operators and manufacturing sites generating oxoanions often desire to monitor the concentration of oxoanions present in process streams, such as waste water streams being released to the environment. Oxoanion concentration information can also be used to establish or adjust a treatment regime intended to reduce the concentration of oxoanions present in a stream before being discharged to the environment.
In practice, oxoanion compositions and concentrations can change over time and with environmental factors. Factors such as rainfall, temperature, industrial process conditions, earthen matter content, and process chemical components can cause changes in the makeup of oxoanions in a given waste water stream over time. Ensuring that the oxoanion concentration in an aqueous stream is accurately and timely measured can help ensure compliance with governmental regulatory requirements and good environmental and health stewardship.